Improve message expiry

[thedevop]

This includes changes:

1. Address @dariopb's issue in Handle MessageExpiryInterval early enough for retained messages to honor it #442
2. Only set pk.Expiry if pk.Properties.MessageExpiryInterval or MaximumMessageExpiryInterval is not zero-value
3. Ensure outgoing pk.Properties.MessageExpiryInterval doesn't contain uint32(of negative value or zero-value) by setting a minimum of 1

[coveralls]

Pull Request Test Coverage Report for Build 13600831491

Details

• 25 of 25 (100.0%) changed or added relevant lines in 2 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.004%) to 98.63%

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Totals
Change from base Build 13530155436:	0.004%
Covered Lines:	6192
Relevant Lines:	6278

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💛 - Coveralls

[mochi-co]

Looks good to me, thank you @thedevop